He talked about the Moment, during their chats. When they weren't two beings whose history and battles stretched across time and space, but were instead just two Gallifreyans. No Lords, no Ladies, no Time for them to dominate. Just two simple aliens from a tiny little planet located in the Constellation of Kasterborous.
He'd talked about how the Moment helped him, showed him the future, exactly the one he needed to see to save Gallifrey. Even if he had to put up with two of his other, less mature selves.
She had said nothing but listened. Her previous incarnations would have no doubt jumped on the opportunity to learn about this doomsday weapon. A weapon of unlimited power, wasted in the hands of a pathetic fool like the Doctor. But she wasn't that man any more, she was someone different, she was starting to see where the Doctor was coming from.
It was the same view he had when he stared at the Moment in front of him. He briefly thought about his previous self, who had decided to go by the name of 'Missy'. He cringed, the same way everyone cringes on their past, thinking their current version was the superior one, with no self-awareness that their future self would do the same thing.
No, this body, it far more suited him. South-Asian, to use the human terminology, not that it made the remote difference to anything. His first few days were awkward, the dresses he previously adored not quite fitting his new body properly, causing him to reluctantly discard them. Still, he'd gotten comfortable in his new body, comfortable enough to hunt out the Moment.
And there it was. A box. Sitting in front of him, covered in Time Lord runes. A box with the power to destroy universes.
"Why are you here?" asked a familiar voice. He looked up to see his previous self standing there, or a copy of her at any rate. He'd never have been caught dead in white and grey, no matter how soft he'd gotten.
"I had to know," the Master said. "I had to see it for myself."
"Well here I am," said the Moment, twirling her body round. "Though I think you've seen this more than enough times."
"You can cease your prattle," the Master said. "You're the conscience of the machine, an artificial intelligence with one too many opinions. Nothing new."
"You summoned me," replied the Moment, having a look around the Master's bare TARDIS.
"A side-effect, nothing more." The Master ignored the copy of his former self, instead trying to get the device to work properly.
"Why do you want to use me?"
"Does it matter?"
"It does to me. I like to know what destruction you're going to wreck, just so I can plan effectively."
"I plan to conquer the universe. With you I can make good on my threat, take out a small galaxy or two. Might even knock off the Milky Way for the hell of it."
"But why?"
The Master looked up at the Moment. Of course, how could a computer ever really understand.
"Why?" he asked, stalking over to the fake woman. "Because he who holds all the cards controls the game. And there's no bigger trump card than this."
"Ah yes, your lust for power," the Moment said. "Your one and only goal, to have power over everything, or to kill it so it doesn't have power over you. So trite."
"What other reason is there to exist in such a meaningless universe? There is no purpose, no grand design, only those who have the courage to seize power and rule."
"So you blow up the galaxy, and then what? Inevitably lose when the Doctor comes round calling?"
"Not this time. The Doctor won't be able to stop me with this."
"Would you like me the list the number of times you thought that? I can, you know? I can see everything in your head. I can see into your past. Your true past, that is."
The Master stopped, pondering what the Moment was saying. Clearly it must be a bluff, but it was an odd one, that was for sure.
"You don't know, do you?" the Moment said. "What the Time Lords really did to you, did they?"
"They put the drumming in my head-" began the Master, only to have the Moment cut him off with a shriek laugh.
"Oh you really have no idea," she said, almost bent double with laughter.
"What's so funny?" snarled the Master, his laser screwdriver slipping into his hand as he prepared to destroy the box.
"Do you want to know the truth about the Time Lords?" the Moment asked.
"What do you mean?" the Master replied cautiously. The Moment waved her hand. Suddenly a portal in the air appeared, shimmering with a golden light found from only one planet.
"That's not possible," the Master said, as he looked back upon the past of his planet.
"You really are a stupid little man, aren't you," said the Moment, rolling her eyes at yet another corporal being's limited view on time. She grabbed the back of the Master's coat and pushed him through before he had a chance to complain.
The Master looked around on the cliff he found himself on. It was Gallifrey alright, but far in its past, before the sun expanded. The familiar golden glow was there, certainly, but not to the same degree as it was in his lifetimes.
He saw two children fighting next to the cliff over some toys, saw one child go over the edge, watched as the child regenerated.
"What is it I'm seeing?" the Master asked.
"The first regeneration on Gallifrey," the Moment said. "The truth hidden deep within the Matrix. The Time Lord's greatest secret."
Images flashed by, images the Master could barely believe, as the Time Lord's shameful history around the Timeless Child was beamed directly into his mind. Then, as suddenly as it began, it ended. He was back aboard his TARDIS.
"Well that was a nice fairytale," he said, still trying to compose himself, refusing to show weakness.
"Don't you want to know what happened to the child?" the Moment asked.
"Not particularly, no. Died one too many times, for all I cared."
"It was the Doctor."
The Master stopped, his entire body frozen. The Doctor... was the child. That was impossible. It must be. Clearly the Moment was trying to unnerve him, to throw him off, to stop him from doing what he wanted.
"Or, it will be," the Moment said. "That is what reality will become if you use me."
"What do you mean?" the Master asked, as he struggled to understand the previous statement and the implications behind it.
"To use me is to occur the greatest punishment one could endure. For the Doctor, it was surviving the Time War. For you..."
"It's turning the Doctor into the most important figure of Time Lord society," said the Master. "Making them more important than I could ever be. Giving them everything I ever wanted."
"Unlimited regenerations. The ability to cheat death for the rest of time. Immortality above all else. That's why you truly want to conquer, isn't it? So death could never touch you. And yet, all this time, your best friend had that power."
"Does the Doctor know?"
"At the moment, no. Not while this is still only a possible timeline. But if you activate me, the Doctor will become the Timeless Child, now and forever."
"It would kill them to find out," the Master said slowly, a small grin forming over his face.
"The Doctor is stronger than that."
"What do you know, you're just an over-opinionated Siri. You don't know the Doctor like I do. This... this will finally bring them down a peg or two. Destroy that arrogant attitude. Make them realize I was right about how meaningless it all was."
"You're willing to make your life worse?"
"If it means defeating the Doctor, to finally vanquish them... yes, without hesitation."
"Then you are exactly who I was made for," the Moment said. "So, Master. Where should I attack first?"
"I have just the idea," the Master said. "Open the portal again. Universal location, not temporal."
The Moment complied, another portal opening up, the Master stepping through to find his old home standing tall. Gallifrey, free from the Time War, hiding at the end of the universe. The Doctor's so-called people, at least at the present moment.
"You could destroy Gallifrey, yes?" the Master asked casually, as he looked upon the citadel, the symbol for all the pain and misery he had been put through at such a young age.
"With ease," the Moment said. "But that's it. By destroying Gallifrey I wouldn't be able to do anything more."
"That's fine by me," the Master said, popping back through the portal to bring the cube to the planet, resting it on the burnt orange sand. "I don't need you any more beyond this. Now, is there a big red button I get to push?"
"There is indeed," said the Moment, the cube whirring, a familiar button appearing. One that was not pushed last time, but this time...
"Before you activate me," the Moment said, giving the Master one last chance. "You're aware that you'll be changing history forever. Wiping out the Time Lords, creating a new fake reality, turning the Doctor into the Timeless Child. You accept the consequence for your action."
"I get revenge on all those that wronged me, while finally proving to the Doctor that I was right all along?" He eagerly placed his hand on the button, wishing that someone was here to witness it. Ah well. He was never going to forget this.
"One last thing," the Moment said. "Why did you make me wear this form?"
The Master turned back to the Moment. He hadn't notice the change, but sure enough, the colours of her clothes had gone from a pristine white to a dark black. Exactly as he liked it.
"As a promise," he said. "To never make the same mistakes I made when I was her ever again. Because I am the Master. The destroyer of worlds. The conqueror of death. The true victor of the Time War. The universe will be mine, and it-" he pressed the button, before stepping back into the portal to avoid being caught in the result explosion, a light so bright that it defied comprehension.
"will obey me."